Keywords:

Gravity coverages;

Hemisphere solution;

Pellinen rule;

Satellite and terrestrial solutions;

Terrestrial gravity information

Summary

The accuracies of recent solutions of potential coefficients as determined from satellite and from terrestrial gravity data are compared. Certain terrestrial solutions are better than others. The determination of the potential coefficients from terrestrial gravity data is considered from the point of view of the variances of the coefficients and the correlation of the coefficients. Coefficients of degree n can be strongly correlated with coefficients of degree n + 1 and to a lesser extent with coefficients of degree n + 2. For existing terrestrial gravity data, these correlations may reach 0.8. These results suggest that significant aliasing error may exist in determinations of potential coefficients from terrestrial gravity data. This error could be reduced by solving for coefficients to degree n + 2 and retaining only those to degree n as a useful set. Tests are made, postulating various improvements in existing surface gravity, to estimate possible corresponding improvement in the potential coefficients.